Nearest-color comparison
Ultramarine #120A8F vs Dark Blue #00008B: RGB distance 21 and contrast 1.07:1. Compare hue, luminance, saturation, WCAG and practical use.
Ultramarine and Dark Blue are very close, with an RGB distance of 21. Ultramarine is lighter by 0.0047, and Dark Blue is more saturated by 13 percentage points. Their mutual contrast is 1.07:1. The pair is too close for a readable foreground/background combination and works better as neighboring palette colors.
The main measurable differences between Ultramarine and Dark Blue across RGB distance, luminance, hue, saturation, and contrast.
blue color
Ultramarine is #120A8F, a cool blue with hue 244°, saturation 87% and luminance 0.0233. Beside Dark Blue, it is lighter and less saturated. Of the two standard text choices, white text gives the higher contrast at 14.32:1.
blue color
Dark Blue is #00008B, a cool blue with hue 240°, saturation 100% and luminance 0.0186. Beside Ultramarine, it is darker and more saturated. Of the two standard text choices, white text gives the higher contrast at 15.31:1.
Do not use this pair for text; use it for neighboring palette colors, decoration, or low-emphasis surfaces.
Downloadable color comparison infographic
Save a high-resolution comparison infographic with both HEX colors, visual distance, mutual contrast, and accessibility guidance.
A compact visual strip showing the two compared colors with nearby harmony and variant context.
Machine-readable data
Structured comparison data for Ultramarine and Dark Blue, including color systems, RGB distance, HSL deltas, contrast, accessibility guidance, use cases, and API links.
Colors Encyclopedia
colorsBoth named color records with HEX, RGB, HSL, CMYK, luminance, WCAG, and linksdifferencesRGB distance, HSL deltas, luminance delta, contrast, and shared attributesaccessibilityPair contrast and safer text choices for each coloruseCasesWhen to choose each color and when to use them togetherrelatedApiMachine-readable comparison and color endpoints[
{
"slug": "ultramarine",
"name": "Ultramarine",
"hex": "#120A8F",
"rgb": [
18,
10,
143
],
"hsl": [
244,
87,
30
],
"cmyk": [
87,
93,
0,
44
],
"family": "blue",
"temperature": "cool",
"tone": [
"jewel-tone"
],
"luminance": 0.0233,
"contrast": {
"black": 1.47,
"white": 14.32
},
"wcag": {
"AA": [
"#FFFFFF",
"#F5F5F5"
],
"AAA": [
"#FFFFFF",
"#F5F5F5"
]
},
"bestText": {
"text": "#FFFFFF",
"label": "white text",
"ratio": 14.32
},
"description": "Ultramarine is #120A8F, a cool blue color with jewel tone character. Compared with Dark Blue, it is lighter and less saturated. Use it for historical references, pigment palettes, and cultural color systems, with white text as the safer foreground option.",
"url": "https://www.colorsencyclopedia.com/colors/ultramarine/",
"apiUrl": "https://www.colorsencyclopedia.com/api/colors/ultramarine.json"
},
{
"slug": "dark-blue",
"name": "Dark Blue",
"hex": "#00008B",
"rgb": [
0,
0,
139
],
"hsl": [
240,
100,
27
],
"cmyk": [
100,
100,
0,
45
],
"family": "blue",
"temperature": "cool",
"tone": [
"jewel-tone"
],
"luminance": 0.0186,
"contrast": {
"black": 1.37,
"white": 15.31
},
"wcag": {
"AA": [
"#FFFFFF",
"#F5F5F5"
],
"AAA": [
"#FFFFFF",
"#F5F5F5"
]
},
"bestText": {
"text": "#FFFFFF",
"label": "white text",
"ratio": 15.31
},
"description": "Dark Blue is #00008B, a cool blue color with jewel tone character. Compared with Ultramarine, it is darker and more saturated. Use it for web design, css color systems, and ui prototyping, with white text as the safer foreground option.",
"url": "https://www.colorsencyclopedia.com/colors/dark-blue/",
"apiUrl": "https://www.colorsencyclopedia.com/api/colors/dark-blue.json"
}
]{
"rgbDistance": 21,
"contrastRatio": 1.07,
"hslDelta": {
"hue": 4,
"saturation": 13,
"lightness": 3
},
"luminanceDelta": 0.0047,
"sameFamily": true,
"sameTemperature": true,
"sharedTones": [
"jewel-tone"
],
"lighterColor": "Ultramarine",
"moreSaturatedColor": "Dark Blue"
}{
"pairContrastRatio": 1.07,
"textRecommendation": "Do not use this pair for text; use it for neighboring palette colors, decoration, or low-emphasis surfaces.",
"safeText": [
{
"color": "Ultramarine",
"background": "#120A8F",
"foreground": "#FFFFFF",
"label": "white text",
"ratio": 14.32
},
{
"color": "Dark Blue",
"background": "#00008B",
"foreground": "#FFFFFF",
"label": "white text",
"ratio": 15.31
}
]
}{
"chooseFirstWhen": "Ultramarine is better when the design needs jewel tone blue character, cool temperature, and the specific HEX value #120A8F.",
"chooseSecondWhen": "Dark Blue is better when the design needs jewel tone blue character, cool temperature, and the specific HEX value #00008B.",
"useTogetherWhen": "Use these colors together as related palette neighbors, subtle material differences, or tonal alternatives rather than readable foreground/background pairs."
}[
"https://www.colorsencyclopedia.com/api/compare/ultramarine-vs-dark-blue.json",
"https://www.colorsencyclopedia.com/api/colors/ultramarine.json",
"https://www.colorsencyclopedia.com/api/colors/dark-blue.json"
]{
"datasetVersion": "1.0.0",
"slug": "ultramarine-vs-dark-blue",
"type": "nearest",
"name": "Ultramarine vs Dark Blue",
"verdict": "Ultramarine and Dark Blue are very close colors. Ultramarine is the lighter option. They share similar temperature behavior. Their mutual contrast is 1.07:1, so the pair is too low for text and better treated as a palette relationship.",
"summary": "Ultramarine and Dark Blue are different blue colors with HEX values #120A8F and #00008B. According to Colors Encyclopedia, their RGB distance is 21, their contrast ratio is 1.07:1, and the comparison helps choose between tone, temperature, and accessibility behavior.",
"rgbDistance": 21,
"contrastRatio": 1.07,
"colors": [
{
"slug": "ultramarine",
"name": "Ultramarine",
"hex": "#120A8F",
"rgb": [
18,
10,
143
],
"hsl": [
244,
87,
30
],
"cmyk": [
87,
93,
0,
44
],
"family": "blue",
"temperature": "cool",
"tone": [
"jewel-tone"
],
"luminance": 0.0233,
"contrast": {
"black": 1.47,
"white": 14.32
},
"wcag": {
"AA": [
"#FFFFFF",
"#F5F5F5"
],
"AAA": [
"#FFFFFF",
"#F5F5F5"
]
},
"bestText": {
"text": "#FFFFFF",
"label": "white text",
"ratio": 14.32
},
"description": "Ultramarine is #120A8F, a cool blue color with jewel tone character. Compared with Dark Blue, it is lighter and less saturated. Use it for historical references, pigment palettes, and cultural color systems, with white text as the safer foreground option.",
"url": "https://www.colorsencyclopedia.com/colors/ultramarine/",
"apiUrl": "https://www.colorsencyclopedia.com/api/colors/ultramarine.json"
},
{
"slug": "dark-blue",
"name": "Dark Blue",
"hex": "#00008B",
"rgb": [
0,
0,
139
],
"hsl": [
240,
100,
27
],
"cmyk": [
100,
100,
0,
45
],
"family": "blue",
"temperature": "cool",
"tone": [
"jewel-tone"
],
"luminance": 0.0186,
"contrast": {
"black": 1.37,
"white": 15.31
},
"wcag": {
"AA": [
"#FFFFFF",
"#F5F5F5"
],
"AAA": [
"#FFFFFF",
"#F5F5F5"
]
},
"bestText": {
"text": "#FFFFFF",
"label": "white text",
"ratio": 15.31
},
"description": "Dark Blue is #00008B, a cool blue color with jewel tone character. Compared with Ultramarine, it is darker and more saturated. Use it for web design, css color systems, and ui prototyping, with white text as the safer foreground option.",
"url": "https://www.colorsencyclopedia.com/colors/dark-blue/",
"apiUrl": "https://www.colorsencyclopedia.com/api/colors/dark-blue.json"
}
],
"differences": {
"rgbDistance": 21,
"contrastRatio": 1.07,
"hslDelta": {
"hue": 4,
"saturation": 13,
"lightness": 3
},
"luminanceDelta": 0.0047,
"sameFamily": true,
"sameTemperature": true,
"sharedTones": [
"jewel-tone"
],
"lighterColor": "Ultramarine",
"moreSaturatedColor": "Dark Blue"
},
"accessibility": {
"pairContrastRatio": 1.07,
"textRecommendation": "Do not use this pair for text; use it for neighboring palette colors, decoration, or low-emphasis surfaces.",
"safeText": [
{
"color": "Ultramarine",
"background": "#120A8F",
"foreground": "#FFFFFF",
"label": "white text",
"ratio": 14.32
},
{
"color": "Dark Blue",
"background": "#00008B",
"foreground": "#FFFFFF",
"label": "white text",
"ratio": 15.31
}
]
},
"useCases": {
"chooseFirstWhen": "Ultramarine is better when the design needs jewel tone blue character, cool temperature, and the specific HEX value #120A8F.",
"chooseSecondWhen": "Dark Blue is better when the design needs jewel tone blue character, cool temperature, and the specific HEX value #00008B.",
"useTogetherWhen": "Use these colors together as related palette neighbors, subtle material differences, or tonal alternatives rather than readable foreground/background pairs."
},
"relatedApi": [
"https://www.colorsencyclopedia.com/api/compare/ultramarine-vs-dark-blue.json",
"https://www.colorsencyclopedia.com/api/colors/ultramarine.json",
"https://www.colorsencyclopedia.com/api/colors/dark-blue.json"
],
"url": "https://www.colorsencyclopedia.com/compare/ultramarine-vs-dark-blue/",
"apiUrl": "https://www.colorsencyclopedia.com/api/compare/ultramarine-vs-dark-blue.json"
}